For presentation of information on certain types of sheetshaped information carriers, for example overhead sheets, there is no simple and efficiently operated solution. Usually the overhead sheets are handled separately which is relatively complicated and sometimes results in mistakes, such as incorrect positioning of the sheets, which is a serious disadvantage in connection with for example a lecture. An automatically operated motordriven device has been developed which however is very expensive and very complicated and consequently sensitive to operation disturbances.
Also within other fields, for example in connection with presentation of brochure materials there is a demand for a new and promotional way of information which for example enables to study of information simoultaneously by two persons which are positioned opposite to each other.